Voltage regulators in use
WARNING!
All regulators connected to Samovar must be physically isolated in terms of voltage. These can be
relays, optocouplers, data bus isolators such as ADUM, etc.
Never connect the regulators directly, otherwise the mains voltage will reach you and Samovar. The best that can happen in that case is that Samovar burns out. Other consequences will be much worse.
Samovar 7.00: the regulator type is selected on the "Regulator" («Регулятор») tab of the configurator (the "Power regulator" («Регулятор мощности») field): KVIC, RMV-K, SEM_AVR or "Do not use" («Не использовать»). The configurator is started with the script flash_windows.bat or flash_macos_linux.sh and selects the required build environment by itself; the PlatformIO environment names below are given for manual builds.
Samovar works with the following types and models of voltage regulators:
Voltage regulators controlled over the UART protocol
Attention! The algorithm for connecting/disconnecting the load when UART control is used:
Connecting.
After the "Turn heating on" («Включить нагрев») command, Samovar switches on relay No. 1, which in turn switches on the contactor. Then it waits for the time specified in the line
#define SAMOVAR_USE_POWER_START_TIME of the file Samovar_ini.h (2 seconds by default; for SEM_AVR the firmware waits another 3 seconds for the regulator to start) and commands the regulator to apply voltage. This ensures that the contactor closes the load power circuit while there is no voltage in it at that moment, which prevents sparking and extends the contactor life. Simultaneously with the voltage being applied by the regulator, relay No. 4 switches on; it is used to connect the boost heating element (in the modes where the boost heating element is used).
Disconnecting.
After the "Turn heating off" («Отключить нагрев») command, Samovar commands the regulator to cut the voltage, waits for it to be done and after 0.2 seconds switches off relay No. 4 and relay No. 1, which in turn switches off the contactor. If the regulator did not respond to the command, the relays are switched off anyway on timeout, and the alarm "Regulator command timeout" («Таймаут команды регулятора») appears in the messages.
In the configurator select "Power regulator" —
KVIC (this is the default value). In
PlatformIO it corresponds to the
Samovar environment. The whole block is explained in the section
Sketch setup.
Fully compatible with Samovar. The adjustment step on the encoder is 0.5 volt. Stabilization is 0.1 volt. It can be shut down in an emergency by an independent sensor.
2. Regulator RMV-K (only versions No. 5 and 6 work with Samovar)
All RMV-K models have power isolation on the control contacts by default, and no modification is needed to work with Samovar.
In the configurator select "Power regulator" — RMV-K. In PlatformIO it corresponds to the Samovar_rmvk environment (the SAMOVAR_USE_RMVK directive). The firmware enables the general regulator support automatically.
The adjustment step, both on the regulator and from Samovar, is 1 volt. Stabilization is 1 volt. Version No. 6 can be shut down in an emergency by an independent sensor. Through the RMV-K, Samovar fully controls the boost, the stabilization and the emergency heating shutdown.
Attention! Since the RMV-K works only with whole values when the stabilization voltage is set, this has a peculiarity when Samovar works in the pre-flooding mode.
3. Regulator SEM_AVR
In the configurator select "Power regulator" — SEM_AVR. In PlatformIO it corresponds to the Samovar_sem environment (the SAMOVAR_USE_SEM_AVR directive). The firmware enables the RMV-K protocol support and the general regulator support automatically.
Compatible with Samovar. It has a peculiarity: in the Samovar interface the power delivered to the load is set and displayed not in volts (as with the two previous regulators) but in watts.
To work correctly with Samovar, use the Stab-avr.ino sketch that comes with Samovar and is located in the directory ...Samovar\Stab-avr
Voltage regulators with no external control over protocols.
For example:
RM2, RM2M, RM2-Pro (hereinafter simply RM
) .
All RM models have power isolation on the control contacts by default, and no modification is needed to work with Samovar.
If Samovar does not control the regulator over UART, select "Power regulator" —
"Do not use" («Не использовать») in the configurator. In
PlatformIO it corresponds to the
Samovar_no_power environment: the
SAMOVAR_USE_POWER,
SAMOVAR_USE_RMVK and
SAMOVAR_USE_SEM_AVR directives are off. The
NBK mode is not available in such a build.
Controlling these regulators comes down to two parameters:
- Switching the regulator itself on/off.
- Starting/stopping the "Boost" («Разгон») mode
This is implemented with two relays whose contacts control the regulator. On the Samovar command "Turn heating on" («Включить нагрев»),
the contacts of relay No. 1 switch the RM on and at the same time the contacts of relay No. 4 give the command to turn on the "Boost" mode.
When the vapor temperature reaches the value specified in the file Samovar_ini.h : (39° in this case)
//Vapor sensor temperature at which the column switches from boost mode to working mode
#define CHANGE_POWER_MODE_STEAM_TEMP 39
Relay No. 4 opens its contacts and the RM turns off the boost mode. When the run is finished, Samovar switches the RM off with the contacts of relay No. 1.
Attention.
If you turn the heating off and then on again, but the vapor sensor temperature is above the value specified in the sketch, the boost will not turn on.
When the safety system sensors trigger, Samovar switches the RM off completely.
Note:
- All the listed regulators work as independent units and can be used with Samovar without a UART connection, following the principle and algorithm of the RM regulator.
Questions and answers. FAQ
Samovar and the voltage regulator show different power readings. How to fix it?
By and large the absolute power is not that important, but it is possible to make the displayed power readings on the regulator and on Samovar match, and essentially there is only one method.
None of the regulators, Samovar included, measures power. They calculate it like calculators, from two values: the voltage currently applied to the heater and the entered resistance of that heater.
The entered resistance is constant, while the voltage changes. The whole adjustment comes down to choosing the heater resistance value.
You can use the calculated resistance: voltage squared divided by power. The voltage is taken from the nameplate on the heating element. Example for a 3 kW 220 V heating element: 220*220/3000=16.13333333333 Ohm.
Or measure it with a multimeter.
For the RMVk regulators and the Simple one built from Chinese modules (Stab-avr).
Attention! If we are not actually going to heat the boiler, we disconnect the heater.
- In the RMVk you can enter the power and voltage values, and the resistance is calculated automatically. Or enter the resistance and the power is calculated. Video on how to set it up. Watch it, do it, and do not forget to switch the regulator to the watts display mode.
- In the Stab-avr, set the actual mains voltage at the moment with the potentiometer and enter the power of your heater.
Attention! For the Stab-avr, the heating element power must be entered for a mains voltage of 230 volts. If the heater manufacturer specified the power for 220 volts in the datasheet, recalculate it for 230 volts.
Start Samovar heating. There is no point in adjusting anything in the Boost mode — the voltage keeps changing all the time, and so does the power. Give the command from Samovar to set some specific voltage on the regulator (say 170 volts for the RMVk, or 2000 watts for the Stab-avr). The regulators switch to stabilization mode.
Compare the power values displayed in Samovar and on the regulator.
Now there are two ways — either change the resistance value in Samovar (web interface: "Settings" («Настройки»), the "Other" («Прочие») tab, the "Heating element resistance for power calculation" («Сопротивление тэна для расчета мощности») field), which is much more convenient, or change the entered power value in the regulator. The goal is to get the values on the regulator and in Samovar as close as possible.
Regulator Kvic .
It has no power readout. So only Samovar is adjusted, to the power you want to see…
That is the first option
The second is to use a chain: a separate volt-ammeter — regulator — Samovar.
This is convenient if different heating elements are used from time to time and/or the heating elements of the heating element assembly itself are switched.
The volt-ammeter really measures the consumed current and shows the actual power on its display. So if you want Samovar to show this power, just change the heater resistance value in Samovar on the fly.
